In food processing, particularly processing of proteinaceous food products, the speed of cooling is exceedingly critical. Failure to cool a food product sufficiently quickly may lead to undesirable effects on the flavor, aroma, texture or other important characteristics of the food product.
There are two general methods of cooling a hot product and filling a container with the product. In one method, the product is rapidly cooled and afterwards placed in a container. However, since the container is cold-filled, precautions must be taken to prevent post contamination of the product, making the procedure relatively expensive. In another method, the container is hot-filled with the product. Sealing the container while the product is still hot pasteurizes the package and prevents contamination of the product. However, the method does have a disadvantage of slow heat transfer. This is especially true of large drums or containers, wherein it can take hours for the product to cool.
U.S. Pat. No. 5,928,699 to Reznik, the disclosure of which is incorporated herein by reference, provides an improved rapid vacuum cooling system. The system comprises a housing, a hot fluid coil disposed in the housing through which flows a hot product, a cooling liquid disposed in the housing which fully covers the hot fluid coil, a vacuum pump operatively connected to an interior of the housing for reducing pressure in the housing until the cooling liquid boils and forms vapors, and a condensing coil disposed in the housing through which flows a cold fluid, the condensing coil condensing the vapors of the cooling liquid and thereby heating the cold fluid. The hot product transfers heat to the cooling liquid, causing it to boil.
The system of U.S. Pat. No. 5,928,699 solves the abovementioned problems of the art, because it rapidly cools any kind of flowable product in a closed, substantially germ-free system. However, a need still exists for rapid cooling of substances, such as certain vegetable products packaged in a sealed package. Of course, packages cannot flow in a hot fluid coil, and so the system of U.S. Pat. No. 5,928,699 cannot be used to cool them.